Alexander of Terra by Christopher L. Anderson

Alexander Thorsson is a frustrated ex-football player and a cashiered Air Force officer, now living life out of a suitcase as an airline pilot. He always thought he'd amount to something more—the people of the galaxy think so too. The Galactics have watched Humans for thousands of years; Humans are the most physically powerful, most adaptable and most brutally brilliant sentients in the galaxy. However, when Alexander the Great boasted that his conquests would continue, “Even to the everlasting and innumerable stars.” the Galactics took him at his word. They live in constant fear that someday Alexander will rise again and lead his legions to conquer the stars. Everyone knows this except Humans—and Alexander. Still, the exotic and masterful Nazeera of Chem kidnaps Alexander from Terra and sentences him to death on the fantastic prison planet of Pantrixnia. That should have been the end of Alexander but somehow he refuses to die quietly; given one final chance at destiny Alexander forges ahead and becomes the legend everyone was afraid of. Galactic conspiracy revolves around him, splintering the Galactics into factions vying to ally with Alexander, negotiate with him or to destroy the threat of Alexander and Earth for all time. Earth is caught between its own brutal history and the reality of its insignificance; only Alexander can save his planet from destruction and save the Galactics from destroying themselves.